1. Field of the Invention
The present invention relates to a sensor, in particular to a ball-rolling type orientation sensor.
2. Description of Related Art
As the popularization of the portable electronic apparatuses like digital cameras or camera phones, it has become normal to watch pictures on the screen of them. Therefore, a picture-rotating function which can rotate pictures on the screen while the apparatuses are rotating is gradually added into the portable electronic apparatuses.
Refer to FIG. 1, a conventional tilt sensor 10 is disclosed by the Taiwan patent application No. 95142815. The tilt sensor 10 is installed into the abovementioned apparatuses and can sense the rotation of the apparatuses. Then, the tilt sensor 10 can output corresponding signals for changing the display orientation of pictures. As FIG. 1 shows, the tilt sensor 10 includes a shell 11 having a V-shaped groove 110, a light emitting device 12 used for emitting light into the V-shaped groove 110, two light receivers used for receiving light from the V-shaped groove 110, and a sliding member 14 used for sliding in the V-shaped groove 110. While the tilt sensor 10 is clockwise or counterclockwise rotated relative to the direction of gravity, the sliding member 14 is going to slide from the central lower position toward the two upper sides of the V-shaped groove 110.
When the sliding member 14 is located at the central lower position of the V-shaped groove 110, the sliding member 14 blocks the light emitting device 12 from emitting light into the V-shaped groove. Then, the light receivers 13 sense no light from the V-shaped groove 110. When the sliding member 14 is located at either upper side of the V-shaped groove 110, the sliding member 14 blocks one of the light receivers 13 so that the light receiver 13 can not receive light from the V-shaped groove 110, but the other light receiver 13 can receive light without any affection. Therefore, the tilt sensor 10 can output a corresponding signal to control the display orientation of pictures.
However, since the sliding member 14 is only able to move between the central lower position, the left upper side or right upper side 14, which means that only three kinds of signals can be outputted by the tilt sensor 10. It will limit the applications of the tilt sensor 10. For example, such a tilt sensor 10 can switch the display orientations of the pictures at three positions of a predetermined angle, 90 degrees counterclockwise and 90 degrees clockwise. But, the display orientations of the pictures can not be changed in a continuous way while the portable electronic apparatus is continuously changing its tilting angle.